Print format validation fails on migrate

Reproduce

• Have a custom app built for version-11, containing print formats
• Set up a new server with version-12
• Install custom app and restore database from old server
• Run bench migrate

Error

> bench migrate
Migrating erp.my_company.com
Updating DocTypes for frappe        : [========================================]
Updating DocTypes for erpnext       : [========================================]
Updating DocTypes for my_app       : [========================================]
Traceback (most recent call last):
  File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "frappe-bench/apps/frappe/frappe/utils/bench_helper.py", line 99, in <module>
    main()
  File "frappe-bench/apps/frappe/frappe/utils/bench_helper.py", line 18, in main
    click.Group(commands=commands)(prog_name='bench')
  File "frappe-bench/env/lib/python3.6/site-packages/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "frappe-bench/env/lib/python3.6/site-packages/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "frappe-bench/env/lib/python3.6/site-packages/click/core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "frappe-bench/env/lib/python3.6/site-packages/click/core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "frappe-bench/env/lib/python3.6/site-packages/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "frappe-bench/env/lib/python3.6/site-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "frappe-bench/env/lib/python3.6/site-packages/click/decorators.py", line 17, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "frappe-bench/apps/frappe/frappe/commands/__init__.py", line 26, in _func
    ret = f(frappe._dict(ctx.obj), *args, **kwargs)
  File "frappe-bench/apps/frappe/frappe/commands/site.py", line 266, in migrate
    migrate(context.verbose, rebuild_website=rebuild_website, skip_failing=skip_failing)
  File "frappe-bench/apps/frappe/frappe/migrate.py", line 52, in migrate
    sync_fixtures()
  File "frappe-bench/apps/frappe/frappe/utils/fixtures.py", line 24, in sync_fixtures
    ignore_links=True, overwrite=True)
  File "frappe-bench/apps/frappe/frappe/core/doctype/data_import/data_import.py", line 194, in import_doc
    f, data_import=True, force=True, pre_process=pre_process, reset_permissions=True
  File "frappe-bench/apps/frappe/frappe/modules/import_file.py", line 66, in import_file_by_path
    ignore_version=ignore_version, reset_permissions=reset_permissions)
  File "frappe-bench/apps/frappe/frappe/modules/import_file.py", line 141, in import_doc
    doc.insert()
  File "frappe-bench/apps/frappe/frappe/model/document.py", line 230, in insert
    self.run_before_save_methods()
  File "frappe-bench/apps/frappe/frappe/model/document.py", line 896, in run_before_save_methods
    self.run_method("validate")
  File "frappe-bench/apps/frappe/frappe/model/document.py", line 797, in run_method
    out = Document.hook(fn)(self, *args, **kwargs)
  File "frappe-bench/apps/frappe/frappe/model/document.py", line 1071, in composer
    return composed(self, method, *args, **kwargs)
  File "frappe-bench/apps/frappe/frappe/model/document.py", line 1054, in runner
    add_to_return_value(self, fn(self, *args, **kwargs))
  File "frappe-bench/apps/frappe/frappe/model/document.py", line 791, in <lambda>
    fn = lambda self, *args, **kwargs: getattr(self, method)(*args, **kwargs)
  File "frappe-bench/apps/frappe/frappe/printing/doctype/print_format/print_format.py", line 38, in validate
    frappe.throw(_('{0} is required').format(frappe.bold(_('HTML'))), frappe.MandatoryError)
  File "frappe-bench/apps/frappe/frappe/__init__.py", line 376, in throw
    msgprint(msg, raise_exception=exc, title=title, indicator='red', is_minimizable=is_minimizable)
  File "frappe-bench/apps/frappe/frappe/__init__.py", line 355, in msgprint
    _raise_exception()
  File "frappe-bench/apps/frappe/frappe/__init__.py", line 315, in _raise_exception
    raise raise_exception(msg)
frappe.exceptions.MandatoryError: <b>HTML</b> is required

Caused by this line:

https://github.com/frappe/frappe/blob/e384c826dcc54f2b1f4e697e2dace3e05c849d3a/frappe/printing/doctype/print_format/print_format.py#L37-L38

I tried to remove all print formats containing "custom_format": 1, but the error remained.

[surajshetty3416]

@barredterra It seems suggestion by Chinmay should resolve the issue.

Closing this issue for now. Please re-open if you are still facing this issue.

[Thunderbottom]

okay, is there a fixtures folder with the custom print formats inside your custom app folder?